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Updated: Sep 29, 2026
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Assessment of normal-appearing white and gray matter in patients with primary progressive multiple sclerosis: a
Marco Rovaris1, Marco Bozzali, Giuseppe Iannucci
1Neuroimaging Research Unit, Department of Neuroscience, Scientific Institute and University Ospedale San Raffaele, Via Olgettina 60, 20132 Milan, Italy.
Background:
Diffusion-tensor magnetic resonance imaging is sensitive to the more destructive aspects of multiple sclerosis (MS) evolution occurring outside and within T2-visible lesions and, as a consequence, holds promise for providing a more complete picture of primary progressive (PP) MS-related tissue damage than conventional magnetic resonance imaging.
Objective:
To improve our understanding of PPMS by assessing the extent of occult pathological features in the normal-appearing white and gray matter of the brain using diffusion-tensor magnetic resonance imaging.
Methods:
Ninety-six patients with PPMS, 47 patients with secondary progressive (SP) MS, and 44 healthy control subjects were studied. T2-hyperintense and T1-hypointense lesion volumes were calculated, and the volume of the whole brain tissue was measured. Diffusion-tensor magnetic resonance imaging scans were postprocessed and analyzed to obtain the mean diffusivity and fractional anisotropy histograms from the brain and from the normal-appearing white and gray matter in isolation.
Results:
The mean T2-hyperintense and T1-hypointense lesion volumes were lower in patients with PPMS than in patients with SPMS, while the mean absolute brain volumes were similar in the 2 groups. The average lesion diffusivity was significantly higher in patients with SPMS than in patients with PPMS (P<.001). Histogram-derived metrics of the brain tissue and normal-appearing white and gray matter were significantly different between patients with PPMS and healthy subjects (range, P =.004 to <.001). Average diffusivity values were significantly higher in patients with SPMS than in patients with PPMS for all the tissues studied (range, P =.001 to <.001). Fractional anisotropy histogram-derived quantities did not significantly differ between the 2 patient groups (range, P =.94 to.03).
Conclusion:
This study confirms that, in patients with PPMS, normal-appearing white and gray matter are not spared by disease-related pathological processes, although they are affected to a lesser degree than in patients with SPMS.
